When birding in tropical locations poisonous snakes are something on my mind but I almost never see one. Almost never. Well while birding around Alamos, Sonora in 2018, I came across this imposing pit viper in the late afternoon and instantly decided I had had enough birding for the day.

A major highlight of my Mexican detour on my trip to Arizona in the spring of 2018, we meeting James Rorabough. He is definitely up to speed as a birder but it is herps that specializes in. When I came across and photographed this rattlesnake in southern Sonora, I could not have found a more qualified person to ID it--he literally wrote the book on herps of Sonora. He mentioned that Mexico is the epicenter of rattlesnake evolution and that rattlesnakes frequently hybridize so there is no guarantee that there are not a few genes of other relatives in this specimen which he identified as this species with that caveat.